TW201348347A - Multi-stable electronic inks - Google Patents

Abstract

A multi-stable electronic ink is disclosed. The multi-stable electronic ink includes a non-polar carrier fluid, a colorant particle, and an oligomer having a number average molecular weight between 183 and 20, 000, exclusive.

Description

Multi-stable electronic ink

The present invention relates to a multi-stable electronic ink comprising a non-polar carrier fluid, colorant particles and an oligomer having a number average molecular weight between 183 and 20,000 (excluding 183 and 20,000).

Ultra-thin flexible reflective electronic displays that appear to be printed on paper have received significant attention due to their potential applications in portable computer screens, electronic paper, smart ID cards, and electronic signage. Electro-optic display technologies such as electrophoretic or electrodynamic display technology are an important method of displaying media for this type. In an electrophoretic or motorized display, a pixel electrode or a segmented electrode (an electrode that is electrically isolated in the viewable area of the display) can control the localized position of the charged toner particles in the ink by applying an electric field. The local position of the particles can affect the reflectivity of the pixel or segment electrodes. Disagree with any particular theory, in electronic inks, particles exhibiting good dispersibility and charge properties in non-polar dispersion media can improve the stability of the ink, improve the conversion behavior of the ink, and impart the multi-stability properties of the ink, as follows The text is further discussed. In addition, the use of non-polar dispersion media in electrophoretic or electrodynamic devices minimizes leakage.

As noted previously, electrophoretic and motorized displays can have many applications. Some display applications, such as e-books and other digital signage applications, do not need to be updated at the same rate as video display applications. In one example, instead of updating the rate in fractions of a second, the information displayed in an e-book or another digital signage application may need to be from every few seconds to once a day or every few days. Any rate update. Therefore, if the display does not require constant power Maintaining an image consumes less power when it displays an image, which can result in power savings and a device that can be easily deployed remotely.

Reference is now made in detail to the specific embodiments of the disclosed oligomers and specific embodiments of the multi-stable electronic inks comprising such oligomers. Alternate embodiments are also briefly described where appropriate.

It should be noted that the singular forms "a", "an", "the" and "the" .

As used in the specification and the appended claims, "about" means ±10% deviation caused by, for example, a change in the manufacturing process.

As used herein, "carrier fluid" is a fluid or medium that is filled with a visible area as defined in an electronic ink display and is generally configured as a vehicle in which colorant particles are carried.

A multi-stable or low-power reflective color display or multi-stable display can be distinguished from a conventional display such as a liquid crystal display (LCD), because after the multi-stable display is removed from the power source, the displayed image will remain displayed until The device's power is restored and the image is updated (ie, changed). Thus, "multi-stability" refers to the ability of a device to maintain two or more states after it has been removed from power. When applied to inks, "multi-stability" refers to the ability of an ink to help achieve multiple states in a device. In a multi-stable device capable of having two states, the states are in maximum color saturation (sometimes referred to as "dark state") and minimum color saturation (sometimes referred to as "clear" The state)") appears on these devices, where the minimum and maximum saturation levels are determined by device specifications. In a multi-stable device comprising more than two states, there may be one or more additional different colored states, each state independently having a different degree of color saturation between a maximum color saturation state and a minimum color saturation state.

Therefore, applications that do not require as many image updates as video displays In multi-station or low-power displays, such as e-book readers and kanban applications. For example, an active display can typically be a larger power consuming component in a portable device. Thus, in some portable devices (such as e-books or other kanban displays) where images can remain static for long periods of time, the use of a multi-stable display can allow power to be turned off and saved during such static times, which can result in longer battery life. The device.

100‧‧‧Stacked electro-optic display

102a‧‧‧First display element

102b‧‧‧Second display element

102c‧‧‧ third display element

104‧‧‧First substrate

106‧‧‧First electrode

108‧‧‧ dielectric layer

110‧‧‧ Groove area

112‧‧‧thin layer

112a‧‧‧thin layer

112b‧‧‧thin layer

112c‧‧‧thin layer

114‧‧‧Display unit

116‧‧‧Second electrode

118‧‧‧second substrate

120‧‧‧Non-polar carrier fluid/electronic ink

122‧‧‧Electronic ink/colorant particles

122a‧‧‧Colorant particles

122b‧‧‧Colorant particles

122c‧‧‧Colorant particles

200‧‧‧ Figure

205‧‧‧ Curve

210‧‧‧ Curve

215‧‧‧ Curve

300‧‧‧ Figure

305‧‧‧ Curve

310‧‧‧ Curve

315‧‧‧ Curve

320‧‧‧ Curve

325‧‧‧ Curve

400‧‧‧ images

500a‧‧ images

500b‧‧‧ images

The embodiments will be referred to the following figures, wherein like reference numerals may correspond to similar, but possibly not identical components. For the sake of brevity, reference numerals with previously described functions may or may not be described in conjunction with other figures in which such reference numerals appear.

1 depicts a cross-sectional view of one embodiment of a stacked electro-optic display that includes an ink having the oligomers disclosed herein.

Figure 2 illustrates the intensity of the electro-mechanical device during the specified time period, with relative intensity and time as the coordinates. The electro-mechanical device is self-powered and includes an electronic ink having the magenta pigment and varying amounts of oligomers disclosed herein.

Figure 3 illustrates the intensity of the electrical state of the motored device for a specified period of time, based on relative intensity and time. The motorized device is self-powered and includes an electronic ink having the black pigment and varying amounts of oligomers disclosed herein.

Figure 4 depicts an image displayed in an electrodynamic device using an electronic ink comprising the oligomers described herein after the electrodynamic device has been removed from the power source for 40 minutes.

Figure 5A depicts an image displayed in an electrodynamic device using an electronic ink comprising an oligomer described herein and connected to a power source.

Figure 5B depicts the image displayed in the motor of Figure 5A after the electromechanical device has been disconnected from the power source for 15 hours.

In some examples, the multi-stable display can be a motor that includes a multi-stable ink Pieces or other electro-optic devices. Such a display as described above may only require the power required to change the displayed image without the additional power required to maintain the image. In contrast, motorized displays that use other inks, such as non-multi-stable inks, may require a composite drive scheme for maintaining grayscale control and still images, which can result in the device requiring more power to achieve multi-stable The same function of the device. Additionally, the use of multi-stable inks may allow the use of passive matrix devices that use patterned electrodes in the visible region in place of active matrix devices. Active matrix devices can use more complex transistors in each pixel, and thus can be fabricated more complexly and cost effectively. Thus, the use of multi-stable electronic inks in electrodynamic devices can result in devices with simplified drive schemes and low power consumption that can result in power savings, cost savings, and devices with longer battery life.

However, multi-stable inks are difficult to produce because the mechanism of multi-stability is not fully understood. For example, current commercial multi-stable displays, such as those manufactured by prior art display technology companies, utilize front-to-back particle motion, which can only provide opaque color and white or black-and-white states. Additionally, such displays may not be able to produce a bright state that allows the display to be used in a stacked architecture as described further below, and may rely on color filters to achieve full color. However, color filters such as red, green, and blue filters can typically be arranged side by side in a pixel, which can cause modulation of light within a pixel when all color filters are not required to produce a certain color. The surface area is reduced and the surface area within the pixel for reflecting incident light is reduced. Therefore, the display image obtained using the color filter can have a dull color.

On the other hand and as further described below, the ability to achieve a clear state may allow the display to be placed in a stacked architecture that allows the entire visible area of the display to be used when modulating and reflecting incident light (ie, each pixel) The entire pixel), which allows the display to achieve brighter colors and better brightness. In addition, because the entire viewing area in the display can be used to modulate light, the displays can also have a larger color gamut volume.

In the past, Hewlett-Packard has conducted research on displays that utilize electric construction and rely on pigment compaction, which allows for coloring when the colorant particles are scattered and when The state in which the particles are compacted in a cell or pixel, and the repetitive motion of the scattering and compaction is called "switching". (See, for example, Yeo, J. et al., "Electro-optical Display", U.S. Patent 8,018,642). However, the inks currently used in prior art displays may not work in a stacked version of the motorized architecture, as such inks may not be able to achieve the desired state of providing a display for a stacked color architecture as described further below. The degree of compaction. Therefore, the researchers continued to develop electronic inks for such stacked structures by conducting research on improving conventional stabilization techniques and materials for multi-stable inks. (See, for example, Zhou, ZL et al., "Electronic Inks" published as WO 2011/046562 on April 21, 2011; Zhou, ZL et al., "Dual Color Electronically" published as WO01/046564 on April 21, 2011. Addressable Ink"; and Zhou, ZL et al., "Electronic Inks" published on April 21, 2011 in the form of WO2011/046563.)

Discloses a novel low-power electric electrophoresis or multistable display of electronic ink, wherein the ink comprises a novel multi-stable electron number average molecular weight (M _n) ranging between 183 and 20,000 oligomer (excluding 20,000 and 183) Things. As used herein, &quot;exclusive&quot; is used in the numerical range to exclude the <RTIgt; For example, a value between "1 and 10 (excluding 1 and 10) (1 and 10, exclusive) means any value other than 1 and 10 between 1 and 10.

Although in the past has been much research steady electronic ink includes a polymer, but such studies have focused on non-absorbent high molecular weight polymers, such as M _n greater than 20,000 and typically greater than 100,000 the polymer. The multi-stable electronic inks disclosed herein include lower weight oligomers, i.e., Mn _is between 183 and 20,000 (excluding 183 and 20,000). Disagreeing with any particular theory, the use of lower weight oligomers in electronic inks appears to allow electronic inks to achieve multiple stability due to the balance of forces (including repulsion, gravity, and other forces) between the ink particles while maintaining switching capabilities. In addition, the range of materials suitable for use as low molecular weight oligomer additives in electronic inks is broader than the range of materials suitable for use as higher weight polymer additives in electronic inks because of oligomers and polymer solubility in non-polar media. It depends on the molecular weight of the oligomer or polymer. Because the low molecular weight oligomers and polymers are more soluble, the lower weight oligomers or polymeric materials that are compatible with the non-polar media used in the electronic ink are more compatible than the ones present. High weight oligomers and polymers.

1 illustrates a cross-sectional view of one embodiment of a stacked electro-optic display 100 that includes an ink having oligomers as described herein. The electro-optic display 100 includes a first display element 102a, a second display element 102b, and a third display element 102c. The third display element 102c is stacked on the second display element 102b, and the second display element 102b is stacked on the first display element 102a. Turning now to electronic inks 120, 122 employing the oligomers disclosed herein, examples of such electronic inks can generally include non-polar carrier fluid 120, pigment particles 122, oligomers described herein, and other additives, such as interfacial activity. Agent, dispersant or charge director.

In some examples, each display unit includes a first substrate 104, a first electrode 106, a dielectric layer 108 (including a reservoir or recess region 110, a thin layer 112), a display unit 114, a second electrode 116, and a second substrate. 118. In other examples, the display unit does not include the thin layer 112. Display unit 114 can be populated with electronic inks 120, 122 disclosed herein that include carrier fluid 120 having colorant particles 122. In some embodiments including the thin layer 112, the thin layer 112 can be opaque. In other examples, the thin layer 112 can be transparent. In embodiments including the thin layer 112, the thin layer 112 can comprise a dielectric material or a conductive material. In a particular embodiment, a metallic material such as nickel can be used.

In an embodiment that includes the thin layer 112, the first display element 102a includes a self-aligned thin layer 112a within the recessed region 110. The first display element 102a also includes color former particles 122a having a first color (e.g., cyan) for a full color electro-optic display. The second display element 102b includes a self-aligned thin layer 112b within the recessed region 110. The second display element 102b also includes color former particles 122b having a second color (e.g., magenta) for the full color electro-optic display. The third display element 102c includes a self-aligned thin layer 112c within the recessed region 110. The third display element 102c is also A color former particle 122c having a third color (e.g., yellow) for a full color electro-optic display is included. In other examples, colorant particles 122a, 122b, and 122c can include other suitable colors to provide an additive or subtractive full color electro-optic display.

In the embodiment shown in FIG. 1, in an electro-optic display 100 comprising the electronic inks 120, 122 disclosed herein, the first display element 102a, the second display element 102b, and the third display element 102c are aligned with one another. Likewise, the thin layers 112a, 112b, and 112c are also aligned with each other. In this embodiment, since the recessed regions 110 of the display elements 102a, 102b, and 102c are aligned with the self-aligned thin layers 112a, 112b, and 112c, respectively, the clear aperture of the stacked electro-optic display 100 does not have the Aligned stacked electro-optic displays can be improved.

In an alternative embodiment (not shown), the first display element 102a, the second display element 102b, and the third display element 102c may be offset from one another. Similarly, the thin layers 112a, 112b, and 112c are also offset from each other. In this embodiment, since the recessed regions 110 and the self-aligned thin layers 112a, 112b, and 112c are only a small portion of the total area of each of the display elements 102a, 102b, and 102c, respectively, regardless of the display elements 102a, 102b, and 102c Between the alignments, the stacked electro-optic display 100 can maintain a high pass aperture. As such, the method for fabricating the stacked electro-optic display 100 can be simplified. In the clear optical state, the self-aligned thin layers 112a, 112b, and 112c prevent coloring of the respective display elements due to the colorant particles 122a, 122b, and 122c, respectively. Therefore, a stacked full-color electro-optic display with bright neutral state and precise color control can be provided.

Turning now to electronic inks employing the oligomers described herein and useful in electro-optical displays (such as motorized displays) as described above, examples of such electronic inks can generally include oligomers, non-polar carriers as described herein. Fluid 120, colorant or pigment particles 122 and other additives such as other surfactants, dispersants or charge directors.

As described above, discloses the use of the novel electronic ink additive, wherein the additive is interposed novel oligomers between 183 and 20,000 (20,000 and 183 not included) to M _n. In some examples, the oligomer can have any hydrocarbon monomer or a matrix of decane. Specific examples of the disclosed oligomers may include, but are not limited to, polyisobutylene, polybutene, polyester, polyethylene, polyacrylate, polymethacrylate, polystyrene or poly(dimethyloxane). alkyl). Also, in some examples, the oligomer may further comprise one or more functional groups including, but not limited to, acrylates, alcohols, decylamines, amines, urethanes, carboxylates, epoxy groups , esters, ethers, oximes, imines, ketones, oximes, phosphates, phosphonates, protonated nitrogen, oxiranes, sulfates, sulfonamides or combinations thereof. These functional groups allow the ink to have other functionalities or to modify various properties of the ink.

In some examples, the carrier fluid can act as a vehicle for dispersing the pigment particles and can act as an electrokinetic or electrophoretic medium. In one example, non-polar fluids are used because they reduce current leakage when driving the display and can increase the electric field present in the ink. In some examples, the non-polar carrier fluid can be a fluid having a low dielectric constant k, such as less than about 20 or, in some instances, less than about 2. While driving the electrodes in the display while responding to a sufficient potential or electric field applied to the colorant particles, the colorant particles can be moved or rotated to different points in the display area that can be viewed by the user to produce different images. In other examples, the carrier fluid may also vary with respect to viscosity, electrical resistivity, specific gravity, chemical stability, or toxicity, and in other examples, such differences may be considered when formulating electronic inks. For example, an overly viscous carrier fluid can slow the diffusion or compaction of colorant particles, which can affect the rate of conversion and can result in less effective electronic inks.

In particular, in some examples, the non-polar carrier fluid can include one or more fluids selected from the group consisting of hydrocarbons, halogenated hydrocarbons, partially halogenated hydrocarbons, oxygenated fluids, oxanes, and combinations thereof. Some specific examples of non-polar carrier fluids may include, but are not limited to, perchloroethylene, cyclohexane, dodecane, mineral oil, isoparaffin fluid, cyclopentaoxane, cyclohexyloxane, cyclooctylmethyloxime Alkane or a combination thereof.

In some examples, pigment or colorant particles added to the electronic ink can provide color and charge to the electronic ink. Similar to the carrier fluid in the ink, the different pigment or colorant particles can have different characteristics, such as different sizes, dispersive properties, hue, color, or brightness. In addition, different pigment particles can be further functionalized to contain different functional groups, which can be further modified Variable particle properties including, but not limited to, hydrophilicity and hydrophobicity, acidity and alkalinity or density of the particles.

The pigment particles can be colored pigments or colored polymeric particles in any possible color, such as RGB or CYMK, ranging in size from 10 nm to 10 μm. In some examples, smaller particles, such as quantum dots, having a particle size of 1 to 10 nm may be employed. In other examples, the particle size can be up to a few microns. In addition, organic or inorganic pigments can be used.

The organic and inorganic pigment particles may be selected from the group consisting of black pigment particles, yellow pigment particles, magenta pigment particles, red pigment particles, violet pigment particles, cyan pigment particles, blue pigment particles, green pigment particles, orange pigment particles, brown pigment particles or White pigment particles. In some cases, the organic or inorganic pigment particles may include spot color pigment particles formed from a combination of two or more primary color pigment particles in a predetermined ratio.

Non-limiting examples of suitable inorganic black pigments include carbon black. Examples of the carbon black pigment include a pigment manufactured by Mitsubishi Chemical Co., Japan (such as carbon black No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100 or No. OB); Columbian Chemicals, Marietta, a variety of carbon black pigments in the RAVEN ^® range manufactured by Georgia (such as RAVEN ^® 5750, RAVEN ^® 5250, RAVEN ^® 5000, RAVEN ^® 3500, RAVEN ^® 1255 or RAVEN ^® 700); by Cabot, Boston, A variety of carbon black pigments in the REGAL ^® series, MOGUL ^® series or MONARCH ^® series manufactured by Massachusetts (such as REGAL ^® 400R, REGAL ^® 330R, REGAL ^® 660R, MOGUL ^® L, MONARCH ^® 700, MONARCH ^® 800, MONARCH ^® 880, MONARCH) ^® 900, MONARCH ^® 1000, MONARCH ^® 1100, MONARCH ^® 1300 or MONARCH ^® 1400); or a variety of black pigments manufactured by Evonik Degussa, Parsippany, New Jersey (such as black FW1, black FW2, black FW2V, black FW18, black) FW200, black S150, black S160, black S170, PRINTEX ^® 35, PRINTEX ^® U, PRINTEX ^® V, PRINTEX ^® 140U, special black 5, special black 6A or special black 4) . Non-limiting examples of organic black pigments include nigrosine, such as CI Pigment Black 1.

Other examples of inorganic pigments include metal oxides and ceramics such as oxides of iron, zinc, cobalt, manganese or nickel. Non-limiting examples of suitable inorganic pigments include pigments from Shepherd Color, Inc. (Cincinnati, OH), such as black 10C909A, black 10P922, black 1G, black 20F944, black 30C933, black 30C940, black 30C965, black 376A, black 40P925, black 411A, black 430, black 444, blue 10F545, blue 10G511, blue 10G551, blue 10K525, blue 10K579, blue 211, blue 212, blue 214, blue 30C527, blue 30C588, blue 30C591, blue 385, blue 40P585, blue 424, brown 10C873, brown 10P835, brown 10P850, brown 10P857, brown 157, brown 20C819, green 10K637, green 187B, green 223, green 260, green 30C612, green 30C654, Green 30C678, Green 40P601, Green 410, Orange 10P320, Starlight FL 37, Starlight FL105, Starlight FL500, Purple 11, Purple 11C, Purple 92, Yellow 10C112, Yellow 10C242, Yellow 10C272, Yellow 10P110, Yellow 10P225, Yellow 10P270, Yellow 196, yellow 20P296, yellow 30C119, yellow 30C236, yellow 40P140 or yellow 40P280.

The following is a list of organic pigments that can be processed according to the teachings herein. Non-limiting examples of suitable yellow pigments include CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 4, CI Pigment Yellow 5, CI Pigment Yellow 6, CI Pigment Yellow 7, CI Pigment Yellow 10, CI Pigment Yellow 11, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 16, CI Pigment Yellow 17, CI Pigment Yellow 24, CI Pigment Yellow 34, CI Pigment Yellow 35, CI Pigment Yellow 37, CI Pigment Yellow 53, CI Pigment Yellow 55, CI Pigment Yellow 65, CI Pigment Yellow 73, CI Pigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow 81, CI Pigment Yellow 83, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 95, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Yellow 99, CI Pigment Yellow 108, CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 113, CI Pigment Yellow 114, CI Pigment Yellow 117, CI Pigment Yellow 120, CI Pigment Yellow 124, CI Pigment Yellow 128, CI Pigment Yellow 129, CI Pigment Yellow 133, CI Pigment Yellow 138, CI Pigment Yellow 139, CI Pigment Yellow 147, CI Pigment Yellow 151, CI Pigment Yellow 153, CI Pigment Yellow 154, Pigment Yellow 155, CI Pigment Yellow 167, CI Pigment Yellow 172 Or C.I. Pigment Yellow 180.

Non-limiting examples of suitable magenta or red or violet organic pigments include CI Pigment Red 1, CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 4, CI Pigment Red 5, CI Pigment Red 6, CI Pigment Red 7 , CI Pigment Red 8, CI Pigment Red 9, CI Pigment Red 10, CI Pigment Red 11, CI Pigment Red 12, CI Pigment Red 14, CI Pigment Red 15, CI Pigment Red 16, CI Pigment Red 17, CI Pigment Red 18 , CI Pigment Red 19, CI Pigment Red 21, CI Pigment Red 22, CI Pigment Red 23, CI Pigment Red 30, CI Pigment Red 31, CI Pigment Red 32, CI Pigment Red 37, CI Pigment Red 38, CI Pigment Red 40 , CI Pigment Red 41, CI Pigment Red 42, CI Pigment Red 48 (Ca), CI Pigment Red 48 (Mn), CI Pigment Red 57 (Ca), CI Pigment Red 57:1, CI Pigment Red 88, CI Pigment Red 112, CI Pigment Red 114, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 144, CI Pigment Red 146, CI Pigment Red 149, CI Pigment Red 150, CI Pigment Red 166, CI Pigment Red 168, CI Pigment Red 170, CI Pigment Red 171, CI Pigment Red 175, CI Pigment Red 176, CI Pigment Red 177, CI Pigment Red 178, C. I. Pigment Red 179, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 187, CI Pigment Red 202, CI Pigment Red 209, CI Pigment Red 219, CI Pigment Red 224, CI Pigment Red 245, CI Pigment Violet 19 , CI Pigment Violet 23, CI Pigment Violet 32, CI Pigment Violet 33, CI. Pigment Violet 36, CI Pigment Violet 38, CI Pigment Violet 43 or CI Pigment Violet 50.

Non-limiting examples of blue or cyan organic pigments include CI Pigment Blue 1, CI Pigment Blue 2, CI Pigment Blue 3, CI Pigment Blue 15, CI Pigment Blue 15:3, CI Pigment Blue 15:34, CI Pigment Blue 15 : 4, CI Pigment Blue 16, CI Pigment Blue 18, CI Pigment Blue 22, CI Pigment Blue 25, CI Pigment Blue 60, CI Pigment Blue 65, CI Pigment Blue 66, CI Indigo 4 or CI Indigo 60.

Non-limiting examples of green organic pigments include C.I. Pigment Green 1, C.I. Pigment Green 2, C.I. Pigment Green 4, C.I. Pigment Green 7, C.I. Pigment Green 8, C.I. Pigment Green 10, C.I. Pigment Green 36 or C.I. Pigment Green 45.

Non-limiting examples of brown organic pigments include C.I. Pigment Brown 1, C.I. Pigment Brown 5, C.I. Pigment Brown 22, C.I. Pigment Brown 23, C.I. Pigment Brown 25 and C.I. Pigment Brown, C.I. Pigment Brown 41 Or C.I. Pigment Brown 42.

Non-limiting examples of orange organic pigments include CI Pigment Orange 1, CI Pigment Orange 2, CI Pigment Orange 5, CI Pigment Orange 7, CI Pigment Orange 13, CI Pigment Orange 15, CI Pigment Orange 16, CI Pigment Orange 17, CI Pigment Orange 19, CI Pigment Orange 24, CI Pigment Orange 34, CI Pigment Orange 36, CI Pigment Orange 38, CI Pigment Orange 40, CI Pigment Orange 43, or CI Pigment Orange 66.

In some examples, the colorant particles can be dispersed in a carrier fluid. In one example, the colorant particles can be selected from pigment particles that are self-dispersing in a non-polar carrier fluid. It should be understood, however, that non-dispersible pigment particles may additionally be used as long as the electronic ink includes one or more suitable dispersing agents. Such super dispersants include dispersants, such as by the Lubrizol Corporation, Wickliffe, OH manufacture of SOLSPERSE ^® series hyperdispersant (e.g. SOLSPERSE ® 3000, SOLSPERSE ® 8000, SOLSPERSE ® 9000, SOLSPERSE ® 11200, SOLSPERSE ® 13840, SOLSPERSE ® 16000, SOLSPERSE ® 17000, SOLSPERSE ® 18000, SOLSPERSE ® 19000, SOLSPERSE ® 21000 or SOLSPERSE ® 27000); various dispersants manufactured by BYKchemie, Gmbh, Germany (eg DISPERBYK® 110, DISPERBYK® 163, DISPERBYK ® 170 or DISPERBYK® 180); various dispersants manufactured by Evonik Goldschmidt GMBH LLC, Germany (eg TEGO® 630, TEGO® 650, TEGO® 651, TEGO® 655, TEGO® 685 or TEGO® 1000); or by Sigma-Aldrich, St. A variety of dispersants manufactured by Louis, MO (eg SPAN® 20, SPAN® 60, SPAN® 80 or SPAN® 85).

In some examples, the electronic ink can further include a surfactant. When used in electronic inks, in some examples, the surfactant can be a colorless molecule that is dispersible or soluble in the carrier fluid of the electronic ink. In some examples, the surfactant may be present directly on the surface of the pigment particles or on the resin particles containing the pigment. In such instances, the surfactant can generate a charge on the pigment or colorant particles, can carry a counter charge that stabilizes the ink, or can help prevent aggregation of the colorant particles.

In still other examples, the electronic ink can further include a charge director. As used herein, the term "charge director" refers to a substance that promotes the charging of colorant particles when in use. In one example, the charge director can be basic and can react with the acid modified colorant particles to negatively charge the particles. In other words, the particles can be charged via an acid-base reaction (or mutual use) between the charged director and the acid-modified surface of the particles. It will be appreciated that charged directing agents can also be used in electronic inks to prevent undesirable aggregation of colorants in the carrier fluid. In other examples, the charge director can be acidic and can react (or interact) with the alkali modified colorant particles to positively charge the particles. Further, the particles may be charged by an acid-base reaction (or mutual use) between the charged director and the surface of the alkali-modified particle.

The charge director can be selected from small molecules or polymers capable of forming anti-microcells in a non-polar carrier fluid. The charge directors can be colorless and can tend to be dispersible or soluble in the carrier fluid. In a non-limiting example, the charge director can be selected from a neutral and non-dissociable monomer or polymer, such as polyisobutylene succinimide, having the following molecular structure:

Wherein "n" is an integer selected from the range of 15 to 100.

Another embodiment of a charge directing agent includes an ionizable molecule that is capable of dissociating to form a charge. Non-limiting examples of such charge directors include sodium di-2-ethylhexylsulfosuccinate or dioctyl sulfosuccinate. The molecular structure of dioctyl sulfosuccinate is as follows:

Yet another embodiment of the charge director includes a zwitterionic charge director, such as lecithin. The molecular structure of lecithin is as follows:

Finally, in some examples, the electronic ink can further include other additives such as optical brighteners, polymers, rheology modifiers, surfactants, viscosity modifiers, or combinations thereof.

In some examples, the concentration of colorant particles and other additives, such as dispersants, charge directors, or surfactants, in the electronic ink can range from about 0.5 to 20 weight percent (wt%). In one example, the concentration of the colorant particles in the electronic ink can range from about 1 to 10 wt%. In this example, the carrier fluid constitutes the remaining ink.

2 is a graph of relative intensity and time, illustrating the intensity of the electro-mechanical device in a specified time in FIG. 200, the electro-optic device comprising an ink having a magenta pigment and varying amounts of oligomers disclosed herein. In the three tests, a test by the steps of having a M _n of 1000 polyisobutylene oligomers of 0.03 molar (curve 205), 0.0075 mole (curve 215) and 0.015 mole (curve 210) of the ink solution: The electromotive device including the inks is switched to the bright state, the data is collected within a prescribed time, and the experiment is terminated by forcing the device to a dark state. As can be seen in Figure 200, all three experiments conducted with an ink comprising a polyisobutylene oligomer showed a consistent state of light intensity over time. Thus, all three inks exhibit multi-stable properties, including inks with higher concentrations of polyisobutylene oligomers having slightly better initial bright state retention.

Figure 3 illustrates the intensity of the electrodynamic device in Figure 300 for a specified period of time in terms of relative intensity and time. The electrodynamic device includes an ink having the black pigments and various oligomers disclosed herein. Typical non-polar carrier fluid in those tests, the test M _n of 6995 (curve 310), 10000 (curve 315) and 8012 (curve 320) and two kinds of inks having no disclosed herein, the oligomer, i.e., high Weight hydrocarbon fluid (plot 325) and petroleum hydrocarbon fluid (plot 305). Again, the ink is tested by converting the electromotive device including the inks to a bright state, collecting the data for a specified time, and ending the experiment by forcing the device to a dark state. As can be seen in Figure 300, the inclusion of the oligomers disclosed herein in an electronic ink allows the ink to have a consistently high light intensity over time and thus has multi-stability properties.

Figure 4 depicts an image 400 displayed in an electrodynamic device using an electronic ink comprising the oligomers described herein after the electrodynamic device has been removed from the power source for 40 minutes. As can be seen in image 400, the image is still clearly visible after the electromechanical device has been removed from the power source for 40 minutes, indicating that the electronic ink comprising the oligomers described herein has at least a bi-stable property or, in other words, can be moved from the power source. Maintain a clear state and a single coloring state after opening.

Figure 5A depicts an image 500a displayed in an electrodynamic device using an electronic ink comprising an oligomer disclosed herein and coupled to a power source (not shown), and Figure 5B depicts the electrical device being disconnected from the power source for 15 hours. Thereafter, the image 500b is displayed in the same electric device as that of FIG. 5A. As can be seen in image 500b, the image of the color gradient is still clearly visible after the electromechanical device has been removed from the power source for 15 hours, indicating that the electronic ink comprising the oligomers described herein has multiple stability properties or, in other words, can be self-powered Maintain multiple coloration status after removal.

It will be appreciated that the aforementioned multi-stable electronic ink including oligomers has been described in the context of particular applications to electromechanical devices. However, such inks can also be used in electrophoretic devices and other electro-optical devices.

100‧‧‧Stacked electro-optic display

102a‧‧‧First display element

102b‧‧‧Second display element

102c‧‧‧ third display element

104‧‧‧First substrate

106‧‧‧First electrode

108‧‧‧ dielectric layer

110‧‧‧ Groove area

112a‧‧‧thin layer

112b‧‧‧thin layer

112c‧‧‧thin layer

114‧‧‧Display unit

116‧‧‧Second electrode

118‧‧‧second substrate

120‧‧‧Non-polar carrier fluid/electronic ink

122a‧‧‧Colorant particles

122b‧‧‧Colorant particles

122c‧‧‧Colorant particles

Claims (15)

A multi-stable electronic ink comprising: a non-polar carrier fluid; a colorant particle; and an oligomer having a number average molecular weight between 183 and 20,000 (excluding 183 and 20,000). The electronic ink of claim 1, wherein the oligomer is selected from the group consisting of a hydrocarbon polymer and a siloxane polymer. The electronic ink of claim 2, wherein the oligomer further comprises any functional group. The electronic ink of claim 1, wherein the non-polar carrier fluid is a non-polar solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, partially halogenated hydrocarbons, oxanes, and combinations thereof. The electronic ink of claim 4, wherein the non-polar solvent is selected from the group consisting of perchloroethylene, cyclohexane, dodecane, cyclopentaoxane, cyclohexyloxane, cyclooctylmethylguanidine. Oxytomane, isoparaffin fluid, mineral oil, and combinations thereof. The electronic ink of claim 1, wherein the pigment particles are selected from the group consisting of black pigment particles, yellow pigment particles, magenta pigment particles, red pigment particles, purple pigment particles, cyan pigment particles, blue Pigment particles, green pigment particles, orange pigment particles, brown pigment particles, and white pigment particles. The electronic ink of claim 6, wherein the pigment particles are colored polymeric particles having a size in the range of 10 nm to 10 μm. The electronic ink of claim 1, further comprising a charge director, wherein the charge director is a small molecule or polymer capable of forming an anti-microcell in the non-polar carrier fluid. The electronic ink of claim 1, further comprising an additional additive selected from the group consisting of optical brighteners, polymers, rheology modifiers, surfactants, viscosity modifiers, and combinations thereof. A combination of an electronic display and a multi-stable electronic ink, wherein the electronic display comprises: a first electrode; a second electrode; and a display unit having a recess defined by a dielectric material, the first electrode and the second electrode The display unit contains the electronic ink; and wherein the electronic ink comprises: a non-polar carrier fluid; a colorant particle; and an oligomer having a number average molecular weight between 183 and 20,000 (excluding 183 and 20,000). The combination of claim 10, wherein the electronic display comprises a plurality of display units in a stacked configuration, a combined first electrode and a second electrode, and a plurality of electronic inks having different colors, each display unit having a different Electronic ink of color. A combination of claim 10, wherein the oligomer further comprises any functional group. A combination of claim 10, wherein the non-polar carrier fluid is a non-polar solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, partially halogenated hydrocarbons, oxanes, and combinations thereof. A combination of claim 10, wherein the coloring pigment has a size ranging from 10 nm to 10 μm and is selected from the group consisting of black pigment particles, yellow pigment particles, magenta pigment particles, red pigment particles, purple Pigment particles, cyan pigment particles, blue pigment particles, green pigment particles, orange pigment particles, brown pigment particles, and white pigment particles. The combination of claim 10, wherein the electronic ink further comprises Additives of the following group: a charge director, a surfactant, an optical brightener, a polymer, a rheology modifier, a viscosity modifier, and combinations thereof, and wherein if the additive includes a charge director, the charge guide The agent is a small molecule or polymer capable of forming an anti-microcell in the non-polar carrier fluid.